Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer with unknown etiology and generally poor outcome. It is characterized by diffuse edema (peau d'orange) and redness (erythema), although either the disease itself or case definitions have varied over time and place, confounding temporal trends and geographic variations. In this review, we discuss case definitions for IBC and its clinical characteristics; describe its geographic variation, age and racial distribution, incidence and survival patterns, and summarize the very limited information on its epidemiologic risk factors. We also incorporate emerging data from the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) Program.
KeywordsInflammatory breast cancer; epidemiology; etiologic factors
Case Definition for Inflammatory Breast Cancer (IBC)IBC is an aggressive and lethal form of breast cancer. It is characterized by the clinical appearance of inflammation, with edema and redness of the breast. However, the appearance of inflammation is not due to true physiologic inflammatory response but rather due to pathologic plugging of the dermal lymphatics of the breast with tumor emboli. This condition was first described in 1814 by Sir Charles Bell [14]; but, it was not until 1924 that the term inflammatory breast cancer was proposed by Lee and Tannebaum at the suggestion of James Ewing [56,88]. Prior to this designation, IBC was referred to as von Volkmann's or Wokmann's syndrome in pregnant women, lactation cancer, carcinoma mastitoides, mastitis carcinomatosa, acute encephaloid cancer, acute mammary carcinoma, acute mammary carcinomatosis, acute brawny cancer, acute scirrhous carcinoma, acute medullary carcinoma or carcinoma telangiectaticum [42,53,55,57,71,75,82,90,92]. In all, these expressions implied an acute and aggressive breast cancer, more of a clinical than a pathological entity, often multifocal [13,18,19,33,38,66,75,92], and occurring in young women during pregnancy or lactation [53,55,75,90].The extent of clinical signs required for IBC has not been standardized and has varied from any edema (peau d'orange) and redness (erythema) to edema and redness covering the entire